1. Field of the Invention
The present invention relates to a rotary compressor, particularly to a variable-delivery vane-type rotary compressor which may be used as a refrigerant compressor for an air conditioner for a vehicle or the like.
2. Description of the Background Art
Generally, in order to control discharge in vane-type rotary compressor, a suction port being in communication with the interior of a cam ring is provided on a side-block which covers one end of the cam ring and the position of the suction port is changed, so that the starting position of compression caused by rotation of the vanes is changed.
For example, a variable-delivery vane-type rotary compressor, which is a background art of the present invention, includes an arc-shaped by-pass port, which is provided in a front plate so as to extend beside the cam surface of a cam ring, the end opening of which may open on any radial section of a working chamber, and a rotatable disc having an arc-shaped opening between the front plate and the cam ring. In this compressor, the rotatable disc may rotate by means of an electric motor provided within or outside the compressor so as to change the position of by-pass opening in order to control discharge.
However, since the rotatable disc rotates by means of the motor in these compressors, there is a disadvantage in that power consumption is increased. In addition, since various sensors, such as a pressure sensor, a temperature sensor and an air-quantity sensor, and electrical control circuits are used in order to control actuation of the motor, there are disadvantages in that construction of the compressor is complicated and the manufacturing cost is increased.